[posix] close files on exec (#3977)

This commit adds the *_CLOEXEC flags when opening files. This ensures
files are closed when spawning new processes.

* use LOG_DAEMON as syslog facility
* remove setenv() when forkpty

examples/platforms/posix/flash.c

@@ -78,7 +78,7 @@ otError utilsFlashInit(void)
         create = true;
     }
 
-    sFlashFd = open(fileName, O_RDWR | O_CREAT, 0600);
+    sFlashFd = open(fileName, O_RDWR | O_CREAT | O_CLOEXEC, 0600);
     lseek(sFlashFd, 0, SEEK_SET);
 
     otEXPECT_ACTION(sFlashFd >= 0, error = OT_ERROR_FAILED);

src/posix/platform/hdlc_interface.cpp

@@ -320,7 +320,7 @@ int HdlcInterface::OpenFile(const char *aFile, const char *aConfig)
     int fd   = -1;
     int rval = 0;
 
-    fd = open(aFile, O_RDWR | O_NOCTTY | O_NONBLOCK);
+    fd = open(aFile, O_RDWR | O_NOCTTY | O_NONBLOCK | O_CLOEXEC);
     if (fd == -1)
     {
         perror("open uart failed");
@@ -480,8 +480,9 @@ exit:
 #if OPENTHREAD_CONFIG_POSIX_APP_ENABLE_PTY_DEVICE
 int HdlcInterface::ForkPty(const char *aCommand, const char *aArguments)
 {
-    int fd  = -1;
-    int pid = -1;
+    int fd   = -1;
+    int pid  = -1;
+    int rval = -1;
 
     {
         struct termios tios;
@@ -490,54 +491,30 @@ int HdlcInterface::ForkPty(const char *aCommand, const char *aArguments)
         cfmakeraw(&tios);
         tios.c_cflag = CS8 | HUPCL | CREAD | CLOCAL;
 
-        pid = forkpty(&fd, NULL, &tios, NULL);
-        VerifyOrExit(pid >= 0);
+        VerifyOrExit((pid = forkpty(&fd, NULL, &tios, NULL)) != -1, perror("forkpty()"));
     }
 
     if (0 == pid)
     {
-        const int     kMaxCommand = 255;
-        char          cmd[kMaxCommand];
-        int           rval;
-        struct rlimit limit;
-
-        rval = getrlimit(RLIMIT_NOFILE, &limit);
-        rval = setenv("SHELL", SOCKET_UTILS_DEFAULT_SHELL, 0);
-
-        VerifyOrExit(rval == 0, perror("setenv failed"));
-
-        // Close all file descriptors larger than STDERR_FILENO.
-        for (rlim_t i = (STDERR_FILENO + 1); i < limit.rlim_cur; i++)
-        {
-            close(static_cast<int>(i));
-        }
+        const int kMaxCommand = 255;
+        char      cmd[kMaxCommand];
 
         rval = snprintf(cmd, sizeof(cmd), "exec %s %s", aCommand, aArguments);
         VerifyOrExit(rval > 0 && static_cast<size_t>(rval) < sizeof(cmd),
-                     otLogCritPlat("NCP file and configuration is too long!"));
+                     fprintf(stderr, "NCP file and configuration is too long!");
+                     rval = -1);
 
-        execl(getenv("SHELL"), getenv("SHELL"), "-c", cmd, NULL);
-        perror("open pty failed");
-        exit(OT_EXIT_INVALID_ARGUMENTS);
+        VerifyOrExit((rval = execl(SOCKET_UTILS_DEFAULT_SHELL, SOCKET_UTILS_DEFAULT_SHELL, "-c", cmd, NULL)) != -1,
+                     perror("execl(OT_RCP)"));
     }
     else
     {
-        int rval = fcntl(fd, F_GETFL);
-
-        if (rval != -1)
-        {
-            rval = fcntl(fd, F_SETFL, rval | O_NONBLOCK);
-        }
-
-        if (rval == -1)
-        {
-            perror("set nonblock failed");
-            close(fd);
-            fd = -1;
-        }
+        VerifyOrExit((rval = fcntl(fd, F_GETFL)) != -1, perror("fcntl(F_GETFL)"));
+        VerifyOrExit((rval = fcntl(fd, F_SETFL, rval | O_NONBLOCK | O_CLOEXEC)) != -1, perror("fcntl(F_SETFL)"));
     }
 
 exit:
+    VerifyOrDie(rval == 0, OT_EXIT_FAILURE);
     return fd;
 }
 #endif // OPENTHREAD_CONFIG_POSIX_APP_ENABLE_PTY_DEVICE

src/posix/platform/logging.c

@@ -46,7 +46,7 @@ void platformLoggingInit(const char *aName)
 #if (OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED) || \
     (OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_NCP_SPINEL)
 
-    openlog(aName, LOG_PID, LOG_USER);
+    openlog(aName, LOG_PID, LOG_DAEMON);
     setlogmask(setlogmask(0) & LOG_UPTO(LOG_DEBUG));
 
 #else

src/posix/platform/misc.c

@@ -30,11 +30,14 @@
 #include "platform-posix.h"
 
 #include <assert.h>
+#include <fcntl.h>
 #include <setjmp.h>
+#include <sys/socket.h>
 #include <unistd.h>
 
 #include <openthread/platform/misc.h>
 
+#include "code_utils.h"
 #include "openthread-system.h"
 #include "common/logging.hpp"
 
@@ -123,3 +126,27 @@ void VerifyOrDie(bool aCondition, int aExitCode)
         exit(aExitCode);
     }
 }
+
+int SocketWithCloseExec(int aDomain, int aType, int aProtocol)
+{
+    int rval = 0;
+    int fd   = -1;
+
+#ifdef __APPLE__
+    otEXPECT_ACTION((fd = socket(aDomain, aType, aProtocol)) != -1, perror("socket(SOCK_CLOEXEC)"));
+
+    otEXPECT_ACTION((rval = fcntl(fd, F_GETFD, 0)) != -1, perror("fcntl(F_GETFD)"));
+    otEXPECT_ACTION((rval = fcntl(fd, F_SETFD, rval | FD_CLOEXEC)) != -1, perror("fcntl(F_SETFD)"));
+#else
+    otEXPECT_ACTION((fd = socket(aDomain, aType | SOCK_CLOEXEC, aProtocol)) != -1, perror("socket(SOCK_CLOEXEC)"));
+#endif
+
+exit:
+    if (rval == -1 && fd != -1)
+    {
+        VerifyOrDie(close(fd) == 0, OT_EXIT_FAILURE);
+        fd = -1;
+    }
+
+    return fd;
+}

src/posix/platform/netif.cpp

@@ -386,8 +386,8 @@ void platformNetifInit(otInstance *aInstance)
 {
     struct ifreq ifr;
 
-    sIpFd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_IP);
-    VerifyOrExit(sIpFd > 0);
+    sIpFd = SocketWithCloseExec(AF_INET6, SOCK_DGRAM, IPPROTO_IP);
+    VerifyOrExit(sIpFd >= 0);
 
     sNetlinkFd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
     VerifyOrExit(sNetlinkFd > 0);
@@ -403,7 +403,7 @@ void platformNetifInit(otInstance *aInstance)
         VerifyOrExit(bind(sNetlinkFd, reinterpret_cast<struct sockaddr *>(&sa), sizeof(sa)) == 0);
     }
 
-    sTunFd = open(OPENTHREAD_POSIX_TUN_DEVICE, O_RDWR);
+    sTunFd = open(OPENTHREAD_POSIX_TUN_DEVICE, O_RDWR | O_CLOEXEC);
     VerifyOrExit(sTunFd > 0, otLogCritPlat("Unable to open tun device %s", OPENTHREAD_POSIX_TUN_DEVICE));
 
     memset(&ifr, 0, sizeof(ifr));

src/posix/platform/platform-posix.h

@@ -399,6 +399,20 @@ void VerifyOrDie(bool aCondition, int aExitCode);
  */
 void SuccessOrDie(otError aError);
 
+/**
+ * This function creates a socket with SOCK_CLOEXEC flag set.
+ *
+ * @param[in]   aDomain     The communication domain.
+ * @param[in]   aType       The semantics of communication.
+ * @param[in]   aProtocol   The protocol to use.
+ *
+ * @returns The file descriptor of the created socket.
+ *
+ * @retval  -1  Failed to create socket.
+ *
+ */
+int SocketWithCloseExec(int aDomain, int aType, int aProtocol);
+
 #ifdef __cplusplus
 }
 #endif

src/posix/platform/settings.cpp

@@ -77,7 +77,7 @@ static int swapOpen(void)
     int  fd;
 
     getSettingsFileName(fileName, true);
-    fd = open(fileName, O_RDWR | O_CREAT | O_TRUNC, 0600);
+    fd = open(fileName, O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0600);
     VerifyOrDie(fd != -1);
 
     return fd;
@@ -152,7 +152,7 @@ void otPlatSettingsInit(otInstance *aInstance)
         char fileName[kMaxFileNameSize];
 
         getSettingsFileName(fileName, false);
-        sSettingsFd = open(fileName, O_RDWR | O_CREAT, 0600);
+        sSettingsFd = open(fileName, O_RDWR | O_CREAT | O_CLOEXEC, 0600);
     }
 
     VerifyOrDie(sSettingsFd != -1);

src/posix/platform/sim.c

@@ -84,7 +84,7 @@ void otSimInit(void)
     sockaddr.sin_port        = htons(kBasePort + sPortOffset + sNodeId);
     sockaddr.sin_addr.s_addr = INADDR_ANY;
 
-    sSockFd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    sSockFd = SocketWithCloseExec(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 
     if (sSockFd == -1)
     {

src/posix/platform/uart.c

@@ -60,17 +60,6 @@ static bool           sEnabled     = false;
 static const uint8_t *sWriteBuffer = NULL;
 static uint16_t       sWriteLength = 0;
 
-#if OPENTHREAD_ENABLE_POSIX_APP_DAEMON
-static void set_flag_cloexec(int a_fd)
-{
-    int ret = fcntl(a_fd, F_GETFD, 0);
-    VerifyOrDie(ret != -1, OT_EXIT_FAILURE);
-    ret |= FD_CLOEXEC;
-    ret = fcntl(a_fd, F_SETFD, ret);
-    VerifyOrDie(ret != -1, OT_EXIT_FAILURE);
-}
-#endif // OPENTHREAD_ENABLE_POSIX_APP_DAEMON
-
 otError otPlatUartEnable(void)
 {
     otError error = OT_ERROR_NONE;
@@ -78,17 +67,14 @@ otError otPlatUartEnable(void)
     struct sockaddr_un sockname;
     int                ret;
 
-    sUartSocket = socket(AF_UNIX, SOCK_STREAM, 0);
+    sUartSocket = SocketWithCloseExec(AF_UNIX, SOCK_STREAM, 0);
 
     if (sUartSocket == -1)
     {
-        perror("socket");
         exit(OT_EXIT_FAILURE);
     }
 
-    set_flag_cloexec(sUartSocket);
-
-    sUartLock = open(OPENTHREAD_POSIX_APP_SOCKET_LOCK, O_CREAT | O_RDONLY, 0600);
+    sUartLock = open(OPENTHREAD_POSIX_APP_SOCKET_LOCK, O_CREAT | O_RDONLY | O_CLOEXEC, 0600);
 
     if (sUartLock == -1)
     {
@@ -96,8 +82,6 @@ otError otPlatUartEnable(void)
         exit(OT_EXIT_FAILURE);
     }
 
-    set_flag_cloexec(sUartLock);
-
     if (flock(sUartLock, LOCK_EX | LOCK_NB) == -1)
     {
         perror("flock");
@@ -290,7 +274,10 @@ void platformUartProcess(const fd_set *aReadFdSet, const fd_set *aWriteFdSet, co
         }
         else if (rval <= 0)
         {
-            perror("UART read");
+            if (rval != 0)
+            {
+                perror("read(UART)");
+            }
 #if OPENTHREAD_ENABLE_POSIX_APP_DAEMON
             close(sSessionSocket);
             sSessionSocket = -1;

src/posix/platform/udp.cpp

@@ -217,8 +217,8 @@ otError otPlatUdpSocket(otUdpSocket *aUdpSocket)
 
     assert(aUdpSocket->mHandle == NULL);
 
-    fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
-    VerifyOrExit(fd > 0, error = OT_ERROR_FAILED);
+    fd = SocketWithCloseExec(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+    VerifyOrExit(fd >= 0, error = OT_ERROR_FAILED);
 
     aUdpSocket->mHandle = FdToHandle(fd);
 

tools/spi-hdlc-adapter/spi-hdlc-adapter.c

@@ -1138,7 +1138,7 @@ static bool setup_spi_dev(const char *path)
     int           ret;
     sSpiDevPath = path;
 
-    fd = open(path, O_RDWR);
+    fd = open(path, O_RDWR | O_CLOEXEC);
     if (fd < 0)
     {
         perror("open");
@@ -1212,7 +1212,7 @@ static bool setup_res_gpio(const char *path)
         goto bail;
     }
 
-    setup_fd = open(dir_path, O_WRONLY);
+    setup_fd = open(dir_path, O_WRONLY | O_CLOEXEC);
 
     if (setup_fd >= 0)
     {
@@ -1223,7 +1223,7 @@ static bool setup_res_gpio(const char *path)
         }
     }
 
-    sResGpioValueFd = open(value_path, O_WRONLY);
+    sResGpioValueFd = open(value_path, O_WRONLY | O_CLOEXEC);
 
 bail:
 
@@ -1308,7 +1308,7 @@ static bool setup_int_gpio(const char *path)
         goto bail;
     }
 
-    setup_fd = open(dir_path, O_WRONLY);
+    setup_fd = open(dir_path, O_WRONLY | O_CLOEXEC);
 
     if (setup_fd >= 0)
     {
@@ -1322,7 +1322,7 @@ static bool setup_int_gpio(const char *path)
         close(setup_fd);
     }
 
-    setup_fd = open(edge_path, O_WRONLY);
+    setup_fd = open(edge_path, O_WRONLY | O_CLOEXEC);
 
     if (setup_fd >= 0)
     {
@@ -1339,7 +1339,7 @@ static bool setup_int_gpio(const char *path)
         setup_fd = -1;
     }
 
-    sIntGpioValueFd = open(value_path, O_RDONLY);
+    sIntGpioValueFd = open(value_path, O_RDONLY | O_CLOEXEC);
 
 bail: